package com.wang.springframework.beans.factory.support;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.wang.springframework.beans.BeansException;
import com.wang.springframework.beans.PropertyValue;
import com.wang.springframework.beans.PropertyValues;
import com.wang.springframework.beans.factory.DisposableBean;
import com.wang.springframework.beans.factory.InitializingBean;
import com.wang.springframework.beans.factory.config.AutowireCapableBeanFactory;
import com.wang.springframework.beans.factory.config.BeanDefinition;
import com.wang.springframework.beans.factory.config.BeanPostProcessor;
import com.wang.springframework.beans.factory.config.BeanReference;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

/**
 * @author wangjianhua
 * @Description
 * @date 2021/8/25/025 14:32
 **/
public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFactory implements AutowireCapableBeanFactory {

    private InstantiationStrategy instantiationStrategy = new CglibSubclassingInstantiationStrategy();


    @Override
    protected Object createBean(String beanName, BeanDefinition beanDefinition, Object[] args) throws BeansException {
        Object bean = null;
        try
        {
            bean = createBeanInstance(beanDefinition, beanName, args);
            //填充属性
            applyPropertyValues(beanName,bean,beanDefinition);
            //执行bean的初始化方法 和BeanPostProcessor 的前置与后置处理方法
            bean = initializeBean(beanName,bean,beanDefinition);
        }
        catch (Exception e)
        {
            throw new BeansException("Instantiate of bean failed",e);
        }

        //注册实现了 DisposableBean接口的对象
        registerDisposableBeanIfNecessary(beanName,bean,beanDefinition);

        addSingleton(beanName,bean);
        return bean;
    }

    protected void registerDisposableBeanIfNecessary(String beanName,Object bean,BeanDefinition beanDefinition){
        if(bean instanceof DisposableBean || StrUtil.isNotEmpty(beanDefinition.getDestroyMethodName())){
            registerDisposableBean(beanName,new DisposableBeanAdapter(bean, beanName, beanDefinition));
        }
    }


    protected Object createBeanInstance(BeanDefinition beanDefinition,String beanName,Object[] args){
        Constructor<?> constructorToUse = null;
        Class<?> beanClass = beanDefinition.getBeanClass();
        Constructor<?>[] declaredConstructors = beanClass.getDeclaredConstructors();
        for (Constructor<?> ctor : declaredConstructors) {
            if(null != args && ctor.getParameterTypes().length == args.length){
                constructorToUse = ctor;
                break;
            }
        }
        return getInstantiationStrategy().instantiate(beanDefinition,beanName,constructorToUse,args);
    }

    /**
     * bean属性填充
     */
    protected void applyPropertyValues(String beanName,Object bean,BeanDefinition beanDefinition){
        try
        {
            PropertyValues propertyValues = beanDefinition.getPropertyValues();
            for (PropertyValue propertyValue : propertyValues.getPropertyValues()) {

                String name = propertyValue.getName();
                Object value = propertyValue.getValue();

                if(value instanceof BeanReference){
                    BeanReference beanReference = (BeanReference) value;
                    value = getBean(beanReference.getBeanName());
                }

                BeanUtil.setFieldValue(bean,name,value);
            }
        }
        catch (Exception e)
        {
            throw new BeansException("Error setting property values"+beanName);
        }
    }




    /**
     * 初始化bean
     * @param beanName beanName
     * @param bean bean
     * @param beanDefinition beanDefinition
     * @return bean
     */
    private Object initializeBean(String beanName,Object bean,BeanDefinition beanDefinition){
        //1. 执行 BeanPostProcessor Before处理

        Object wrappedBean = applyBeanPostProcessorsBeforeInitialization(bean, beanName);

        //  执行bean对象的初始化方法
        try
        {
            invokeInitMethods(beanName, wrappedBean, beanDefinition);
        }
        catch (Exception e)
        {
            throw new BeansException("Invocation of init method of bean["+beanName+"] failed",e);
        }


        //2. 执行 BeanPostProcessor After处理
        wrappedBean = applyBeanPostProcessorsAfterInitialization(bean,beanName);
        return wrappedBean;
    }

    private void invokeInitMethods(String beanName,Object bean,BeanDefinition beanDefinition) throws Exception{
        //1.实现接口 InitializingBean
        if(bean instanceof InitializingBean){
            ((InitializingBean) bean).afterPropertiesSet();
        }

        //2. 注解配置 init-method 判断是为了避免二次执行销毁
        String initMethodName = beanDefinition.getInitMethodName();
        if(StrUtil.isNotEmpty(initMethodName)){
            Method initMethod = beanDefinition.getBeanClass().getMethod(initMethodName);
            if(null==initMethod){
                throw new BeansException("Could not find an init method named '"+initMethodName+"' on bean with name '"+beanName+"'");
            }
            initMethod.invoke(bean);
        }
    }

    @Override
    public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName) throws BeansException {
        Object result = existingBean;
        for (BeanPostProcessor processor : getBeanPostProcessors()) {
            Object current = processor.postProcessorAfterInitialization(result, beanName);
            if(null == current){
                return result;
            }
            result = current;
        }
        return result;
    }

    @Override
    public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException {
        Object result = existingBean;
        for (BeanPostProcessor processor : getBeanPostProcessors()) {
            Object current = processor.postProcessorBeforeInitialization(result, beanName);
            if(null == current){
                return result;
            }
            result = current;
        }
        return result;
    }

    public InstantiationStrategy getInstantiationStrategy() {
        return instantiationStrategy;
    }

    public void setInstantiationStrategy(InstantiationStrategy instantiationStrategy) {
        this.instantiationStrategy = instantiationStrategy;
    }
}
